When a dinosaur materialises alongside the Houses of Parliament in Victorian London, the Doctor';s old friends the Paternoster Gang are relieved when he arrives, seemingly to deal with the creature. However, time is against him as he must embrace his latest form in order to conquer a sinister threat lurking in the background of events.

All of the current-era Doctors have done a good job of hinting at the anger and darkness that lurks behind the Doctor's larky facade, but Capaldi brings a welcome element of yearning melancholy to the Twelfth Doctor.

For a program known for its harum-scarum pace and keep-up-or-shut-up iconography, the Season 8 Saturday premiere of BBC America's Doctor Who opens slowly - even with the T. rex - and radiates a newly modern self-consciousness.